So, I'm currently enrolled in a 2D Animation class, and our current assignments are to use note cards to make flipbook animations.
The first was just a basic bouncing ball across the page, making contact with a 'floor' at least twice.
The second is a bouncing ball ' perspectively ', meaning that we have to make it large and up close bouncing away and getting smaller or visa versa.
And the third was to start with a circle, turn it into something, then have it turn back into a circle without just doing a ' forward/backward ' animation loop.

Oddly enough, I'm having severe troubles with these assignments because I'm not good at the traditional 2D Animation style of drawing something, and flipping between that page the next to make the next drawing. ._.;

In conclusion: Flipbooks are weird.